Post on 15-Jul-2020
First results from the full-scale prototype for the
Fluorescence detector Array of Single-pixel
TelescopesJohn Farmer for the FAST collaboration:Toshihiro Fujii, Max Malacari, Justin Albury, Jose A. Bellido, John
Farmer, Aygul Galimova, Pavel Horvath, Miroslav Hrabovsky, Dusan Mandat, Ariel Matalon, John N. Matthews, Maria Merolle,
Xiaochen Ni, Libor Nozka, Miroslav Palatka, Miroslav Pech, Paolo Privitera, Petr Schovanek, Stan B. Thomas, Petr Travnicek
(https://www.fast-project.org)
1
FAST Motivation / Concept
FAST Prototypes:
2014 single-pixel
telescope
2016 full-scale prototype
2017 interative designs
Data and Simulations
UHECRs, TA CLF (UV
laser)
FAST-only reconstruction
Future Plans
2
Outline
Lack of statistics in highest-energy UHECR bins
Need a detector with huge aperture
Discrepancies in TA-Auger energy spectra at high energies
Interesting behaviors at high energies:
Increase in elongation rate?
GZK recovery?
Different Auger/TA GZK thresholds?
3
ICRC CRI238
ICRC CRI231
FAST Motivation
Nitrogen fluorescence
detectors common
instruments for UHECR
measurement
Finely-pixelated camera:
ex: Auger FD (440 PMTs),
TA FD
Expensive!
High coverage difficult
FAST: 4 pixels
Low-cost design
Embraces hybrid
detection:
o Geometry / Timing
information: SD/FD array
4
FAST Concept
5
Comparison of FAST / TA FD field of view
FAST vs. Traditional FD Eye
Huge-aperture FD Array targeting the highest-energy UHECRs
Each telescope: 4 PMTs, 30°×30° field of view (FoV)
Each station: 12 telescopes, 48 PMTs, 30°×360° FoV
Triangular grid with 20km spacing 500 stations ⇒
150,000 km2
o Auger: 3,000 km2
o TA: 762 km2
Not possible to entertain FD Array with expensive, highly-pixelated
Auger Array
FAST Array Concept
Full FAST Array Concept
7
①
②
③
⑥ 2014: UHECR detections with
EUSO-TA optics + single-pixel FAST camera (Astropart.Phys. 74 (2016) 64-72, arXiv: 1504.00692) Stable operation under high
background
Detection of 16 highly significant showers
2016: first Full-Scale FAST prototype Remote operation
2017: 2 iterative prototypes to be assembled in September
1
FAST - today
Accepted for publication
in Astroparticle Physics
20142016
FAST Prototypes at TA FD Site
FAST - progress in design and construction
UV Plexiglass Segmented primary mirror 8 inch PMT camera
(2 x 2)
1m2 aperture FOV = 25°x 25°
variable
tilt
Joint Laboratory of Optics Olomouc – Malargue November 2015 3
Prototype - October 2015
15°
45° UV band-pass
filter
8
DAQ System:
Remotely Operated
HV Monitoring System
4 8-inch PMTs (Hamamatsu R5912-03MOD) Calibrated at UChicago
UV band-pass filter (ZWB3)
Segmented mirror of 1.6 m diameter
Externally triggered by TA FD Shared field of view with Black
Rock Mesa site
1st Full FAST Prototype (2016)
9
18 events found by January (120
hours)
Fully remote operation Automated shutdown
procedure
Monitoring via IP camera
Total operation time > 200h
Search for reconstructed events in shared field-of-view with TA FD
Open Close
Highest event: E=1018.55 eV,
Rp=3.0 km by TA FD
1st Prototype Remote
Operation
10
3rd FAST protoype height reduced
Scan in azimuth over TA CLF (vertical UV laser)
Upgrade electronics for self-triggering with FAST
Investigating option for FAST housing: half-size shipping container
Cheap vs cost of custom shed
Currently in negotiation with companies in Chicago
2017 FAST Prototypes
Time (100 ns)0 100 200 300 400 500 600 700 800
/ (
10
0 n
s)p
.e.
N
-30
-20
-10
0
10
20
30
40PMT 1
Time (100 ns)0 100 200 300 400 500 600 700 800
/ (
10
0 n
s)p
.e.
N
-30
-20
-10
0
10
20
30
40PMT 3
Time (100 ns)0 100 200 300 400 500 600 700 800
/ (
10
0 n
s)p
.e.
N
-20
-10
0
10
20
30
PMT 2
Time (100 ns)0 100 200 300 400 500 600 700 800
/ (
10
0 n
s)p
.e.
N
-20
-10
0
10
20
30
40
PMT 4
11
Single event Ultraviolet vertical laser at a
distance of ~21 km, λ = 355 nm
Equivalent to ~1019.5 eV UHECR
Composite eventSimulation vs. data
Simple TA CLF simulation:• 4.4 mJ 355 nm laser. • Pure molecular atmos. • QE 20% • Mirror reflectivity 86.03% • UV trans. 89.46% • FAST azimuth, elev. 300.2˚, 15˚ • FAST pos. 17 km, -12.1 km
TA CLF Measurement
12
① 2016/10/05 06:37:49.525424540 ② 2016/10/05 10:25:50.781802380
TAFD reconstruction
logE = 18.08, Rp = 2.40 kmClose, Cherenkov-
dominated event
UHECR First Light
FAST Simulated
Reconstructions
13
Geometry
(given by
TASD)
Shower Profile
(FAST)
✦Energy: ±10%, Xmax : ±35 g/cm2 at
1019.5 eV.
✦Comparable with current FDs
Simulation 32 EeV
+
FAST only reconstructionFAST hybrid reconstruction
✦Simulated reconstruction with
FD array of 20km spacing
✦Under development
56 EeV Simulation
Installed first full-scale FAST prototype in 2016
Installing two more telescopes in September 2017 (75 x 25 degree FoV)
Upgrade electronics for self-triggering
Add all-sky camera for weather monitoring
Plan to move one telescope to Argentina for TA-Auger cross-calibration
14
Summary and Future Plans
ICRC CRI231
Backup
15
Department of Physics, University of Chicago 7
FIG. 12. SPE peak height dist ribut ion used to set discrimi-
nator threshold value. The pedestal ends at around a heightof 350 ADC counts. Dividing this by the 4095 dynamic range
of the FADC gives a discriminator threshold of ⇡ 85 mV.
in wavelength. A NIST calibrated photodiode providesthe absolute calibrat ion for the incident light flux, deter-mining Nγ through a powermeter readout . The flux isreduced to the SPE level measurable by the PMT usingan integrat ing sphereof known transmission and incorpo-rat ing the light at tenuat ion coefficient of theapparatus13,↵ = (5.828± 0.018)⇥10− 4. Eq. 5 can thus be rewrit ten:
✏=Npe
Nγ
= Npe ⇥hc
Ptλ↵(6)
where λ is the wavelength, P is the powermeter read-ing, and t is the read out t ime for each step. Typicalpowermeter readings are pico-Wat t order-of-magnitude.
As before, we perform a SPE spect rum measurement ,obtaining both thepedestal and SPE peak. We introducea discriminator to the readout elect ronics. The PMT sig-nal goes through the amplifier and into the discriminatorinput . By increasing the discriminator threshold value,we remove the pedestal and ensure that only SPEs are re-ceived. The discriminator value is determined using thepeak height dist ribut ion of SPE events (Fig. 12), takingthe height posit ion after the pedestal peak and dividingit by the dynamic range of the FADC.
Once the discriminator value is set , its output is placedinto a quad t imer to check the rate, and then switched toa scaler to count SPEs. After the setup is complete, with
Wavelength [nm]0 100 200 300 400 500 600 700
Effic
ien
cy [%
]
0
2
4
6
8
10
12
14
16
18
20
22
Detection Efficiency: FAST PMTs
Hamamatsu (Scaled)
PMT ZS0025PMT ZS0024
PMT ZS0022PMT ZS0018
18. HV = 2169V, Disc = 38mV, x20 Amp
22. HV = 2252V, Disc = 50mV, x20 Amp
24. HV = 2266V, Disc = 85mV, x20 Amp
25. HV = 2000V, Disc = 44mV, x20 Amp
FIG. 13. Detect ion efficiency results with Hamamatsu mea-surement for comparison.
the powermeter and monochromator init ialized, any re-maining lights in the lab are switched o↵. The computerin the lab is accessed remotely to begin data acquisi-t ion. The DAQ program cont rols the monochromatorand powermeter. It obtains and averages 10,000 read-ings from the powermeter over 10 s for a given step; theerror, δP , is calculated in quadrature from Poisson stat is-t ics on both powermeter readings, lamp signal and back-ground. The lamp background corresponds to when thepowermeter values are read out while the monochroma-tor shut ter is kept closed; the lamp signal is obtained foran open shut ter. The final power value used in calcu-lat ing detect ion efficiency is the di↵erence between these(P = Pl am p,si g − Pl am p,bk d). The PMT rate, R, is calcu-lated in a similar way, with open and closed shut ters cor-responding to signal and background, respect ively. Thedetect ion efficiency is calculated using Eq. 6, and thestat ist ical error is given by Eq. 7, 8, 9:
δP = P ⇥
s
(δP l a m p , s i g
Pl am p,si g
)2 + (δP l a m p , bk d
Pl am p,bk d
)2 (7)
δR = R ⇥
s
(δR s i g
Rsi g
)2 + (δR bk d
Rbk d
)2 (8)
δ✏,st at = ✏⇥
r
(δP
P)2 + (
δR
R)2 + (
δ↵
↵)2 (9)
A result for thedetect ion efficiency measurement of thePMTs can be found in Fig. 13. The results are plot tedalongside scaled-down data provided by a Hamamatsumeasurement . Hamamatsu only incorporates quantumefficiency, not collect ion efficiency. PMT detect ion effi-ciency peaks at ⇡ 20% close to 400 nm.
From detect ion efficiency results, we observe two“ bumps” near 200 nm and 350 nm. We expect the de-tect ion efficiency to have a smooth peak, as shown in the
1st Prototype PMT Calibrations16
6""
Figure 3: Diagram of experimental setup for the measurement of wavelength-dependent
detection efficiency using a deuterium lamp. The monochromator can be replaced by a mirror,
shown in gray, for measurements of absolute detection efficiency using the laser source. The
number labels correspond to equipment information listed in Table 1 and referenced in the text.
(1) PMT Hamamatsu Photomultiplier Tube, Type
H7195P(R329P)
(2) Detector Newport 918D-UV Photodiode Detectors
(3) Powermeter Newport 2936-C Powermeter
(4) Laser Newport Excelsior 375 CW Laser
(5) Integrating Sphere Newport General Purpose Integrating Sphere, Model
70675
(6) Spectrum Lamp Newport Deuterium Lamp, Model 60000
(7) Lamp Power Supply Newport Deuterium Lamp Power Supply, Model
68840
(8) Monochromator Newport Cornerstone 130TM
Motorized 1/8m
Monochromator, Model 74000
(9) Spectrophotometer Newport Spectrophotometer, Model 77700
(10) Calibration Lamp Newport Pencil Style HgAr Calibration Lamp, Model
6047
Table 1: Equipment List, numbers correspond to diagram in Figure 3
used in AIRFLY experiment
Astropart.Phys. 42 (2013)
90–102
Single photo
electron
Detection efficiency
(QE×CE)KICP @ UChicago
Time (100 ns)
0 100 200 300 400 500 600 700 800
/ (
10
0 n
s)
p.e
.N
-40
-30
-20
-10
0
10
20
30
40
PMT 1
Time (100 ns)
0 100 200 300 400 500 600 700 800
/ (
10
0 n
s)
p.e
.N
-40
-30
-20
-10
0
10
20
PMT 3
Time (100 ns)
0 100 200 300 400 500 600 700 800
/ (
100
ns
)p
.e.
N
-30
-20
-10
0
10
20
30
PMT 2
Time (100 ns)
0 100 200 300 400 500 600 700 800
/ (
100
ns
)p
.e.
N
0
50
100
150
200
250
300
PMT 4
YAP pulser (YAlO3:Ce
scintillator + 241Am
source) attached on
each PMT surface
TA UV LED
used for on-
site
calibration
Wavelength [nm]
Airplane events17
External trigger from TA includes triggers on airplane events
Overwhelmingly common…